1. Field of the Invention:
This invention relates to a valve actuating mechanism, and more particularly to improvements in a mechanism for actuating a particular non-slidable disk type valve which is actuated by a particular cylindrical cam of the type that reciprocates to put a cooperating output shaft into cycles of rotational and seesaw motion, via a cooperative cam follower.
The non-slidable disk type valve herein means a particular valve of the type that has a disk-shaped valve body which is slightly movable toward and away vertically from a stationary valve seat without any slidable relation therebetween and which is rotatable about a horizontal axis to take its releasing position. The valve arrangement according to the invention is advantageously applicable to supply of powder, granule, grains and liquid.
2. Description of the Prior Art:
The non-slidable disk type valve per se for supply of powder, granule, grains and liquid is known and typical examples of such valve are disclosed in Japanese Utility Model Publication No. 59-1998 published on Jan. 19, 1984 (Application No. 55-83462, filed June 14, 1980) and also in Japanese Patent Application Laid-open No. 61-192972, laid-open on Aug. 27, 1986 (Application No. 60-3491d, filed Feb. 22, 1985). In these references, however, there is no teaching about mechanism for actuating such particular non-slidable disk type valve.
On the other hand, the cylindrical cam per se of the above type, which may be utilized to actuate the aforesaid non-slidable disk type valve, is also known and a typical example of such cam is disclosed in Japanese Patent Application Laid-open No. 51-57377, laid-open May 19, 1976 (Application No. 49-131474, filed Nov. 14, 1974). In this reference, however, teaching is directed only to a particular mechanism for actuating a specific conical sliding valve, and there is no teaching about a mechanism for actuating the afore-discussed non-slidable, disk-shaped valve which is a subject matter of the present invention.
An important feature of the invention resides in an advantageous combination of the above-discussed particular non-slidable disk type valve arrangement with an improved particular cylindrical cam arrangement according to the invention, and more specifically in improvements in a joint structure between the valve and the cam arrangements.
Another important feature of the invention resides in a particular application of the improved cylindrical cam arrangement to actuation of the above-discussed non-slidable disk-shaped valve in a more advantageous manner than that of the conventional cam arrangement as disclosed in the aforesaid Japanese Patent Application Laid-open No. 51-57377.
For the purpose of better understanding, the aforesaid conventional cylindrical cam arrangement is herein illustrated in FIG. 12 of the accompanying drawings, wherein a cylindrical cam arrangement includes a hollow, grooved cylindrical body 1 supported rotatably and axially slidably within a stationary casing 2. The cam body 1 has an internal space defined by a cylindrical wall 3 in which a first and a second guide grooves 4, 5 are formed independently.
An seal ring 6 is mounted on the periphery of the cam body for separating the internal space of the casing 2 into two air-tight chambers 7, 8 each connected to an unillustrated external pressure source via air ports 9, 10 formed in the casing wall. More particularly, the port 9 serves as an inlet/outlet for charging pressurized air into or discharging the same from the rear chamber 7 while the other port 10 serves also as an inlet/outlet for charging pressurized air into or discharging the same from the front chamber 8. Thus, the cylindrical cam body 1 is forced to reciprocate by the pressurized air alternately introduced into the chambers 7, 8 via the ports 9, 10.
The first groove 4 has a spiral portion 4a which extends spirally with respect to an axis of the cylindrical body 1, so that a first cam follower 11, which is fixed to the casing 2 and radially extends into relatively movable (slidable or rotatable) engagement with the groove 4, can put the cam body 1 into rotational motion when the cam body reciprocates. The first groove 4 further includes a straight front end portion 4b which extends in parallel with respect to the axis of the cylindrical body 1, so that the first cam follower 11 can impart rectilinear motion to the cylindrical body 1.
The second groove 5 has an axially extending straight portion 5a and an oblique front end portion 5b whose axis is inclined by a certain angle with respect to an axis of the straight portion 5a. The second groove 5 cooperates with a second cam follower 12 supported on a rear end portion of an output shaft 13 which is rotatably and inclinably supported at its enlarged flange 14 with a spherically convexed external surface slidable relative to a spherically concaved internal surface of a bush 15 fixed to a front end portion of the casing 2. The output shaft 13 extends rearward into the internal space of the cam body 1, as shown partially in phantom lines, so that the second cam follower 12 carried on the rear end portion of the shaft 13 extends radially into relatively movable engagement with the second groove 5.
Thus, when the cam body 1 moves rearward (rightward in FIG. 12), so that the second cam follower 12 is in the oblique front end portion 5b while the first cam follower 11 is in the straight front end portion 4b during reciprocation of the cam body, the output shaft 13 is put into seesaw motion.
On the other hand, when the cam body 1 moves forward (leftward in FIG. 12), so that the second cam follower 12 is in the straight portion 5a while the first cam follower 11 is in the spiral portion 4a, the output shaft 13 is forced to rotate about its axis. Consequently, a conical valve body 16, which is connected via a toggle joint 17 to the output shaft 13, is corotated with the shaft 13, so that a passageway for liquid, which is in the form of a cross hole 18 extending through the valve body 16, is coaxially aligned with an inlet passageway 19a and also with an outlet passageway 19b.
As a result, a liquid to be supplied is permitted to flow from the inlet passageway 19a through the valve passageway 18 to the outlet passageway 19b. When the valve body 16 is rotated so that its passageway 18 is not coaxial with the inlet and outlet passageways 19a, 19b, the valve takes its closing position.
As will be apparent from the above description, the prior art cylindrical cam is forced to rotate while reciprocating simultaneously during a greater part of strokes of the cylindrical cam body. Consequently, it is possible to say that the prior art cylindrical cam arrangement of the illustrated type has a disadvantage that the above-described seal ring easily wears out because it undergoes repeated frictions developed by the simultaneous rotation and reciprocation of the cylindrical cam body.
Further, it will be easily understood that the valve actuating mechanism as illustrated and described with reference to FIG. 12 is not readily applicable to actuation of the specific disk-shaped valve as disclosed in the above referenced Japanese Utility Model Publication No. 59-1998 and Japanese Patent Application Laid-open No. 61-192972.